Health warning issued after N.Y. listeria deaths

CDC is investigating a possible food source for the deadly bacterium

ALBANY, N.Y. - Listeria microbes have killed seven people in New York and infected at least 21 others since July, according to the state Health Department.

Health officials are warning the public about the bacterium, which can be transmitted by contaminated food, and poses the greatest risk to newborns, children, pregnant women, the elderly and those with weakened immune systems.

Only 10 of the cases, including eight in New York City, have so far been linked to a national outbreak of the illness, which has prompted an investigation by the Centers for Disease Control and Prevention in Atlanta into a possible food source for the potentially fatal bacterium.

Test results are pending in another four cases, and officials are trying to gather samples from more of the cases, according to Kristine Smith, a New York Health Department spokeswoman.

Unusual numbers of Listeria infections in New Jersey, Connecticut, Michigan, Maryland and Pennsylvania have been reported in recent months.

In Maryland, two people have been diagnosed since July with listeria infections, said state health department spokesman J.B. Hanson. Tests on the patients, who have recovered, show they were infected with the same strain that has sickened others on the East Coast.

Health officials became concerned about a widespread outbreak after a strain of the bacterium found in Pennsylvania was also responsible for sickening eight people in New York City, including two who died. Nine others have died in Pennsylvania, New Jersey and Michigan.

Until a source of the outbreak is identified, health officials are recommending that people avoid certain foods that may be contaminated with the Listeria bacterium, including unpasteurized milk and cheeses, uncooked hot dogs, and luncheon meats, unless they are heated before eating.

In severe cases, Listeria infections can cause meningitis, or inflammation of the tissues around the brain and spinal cord. Symptoms can include severe headaches, high fever, nausea, muscle aches and diarrhea.